The goals of this Core are (i) to obtain, preserve, examine, diagnose, and disseminate human brain tissue from autopsies of patients with Alzheimer's disease (AD), Down'S syndrome, and head injury, as well as appropriate controls, and from resected temporal lobe specimens from patients with chronic intractable temporal lobe epilepsy; (ii) to perform patient genotyping; and (iii) to process, embed, and section animal brain tissues for immunohistochemical investigations and to provide neuropathologic evaluations of these tissues. Continued achievement of these goals will enhance and facilitate achievement of the aims of the Projects in this Program Project. In this way, this Core will facilitate investigations of glial-neuronal relationships underlying early pathogenic events in the development of neuropathologic features of AD.